From f95aecdee15024707723e45fe082ef93c0a629f5 Mon Sep 17 00:00:00 2001
From: Tino Wagner <tino.wagner@zhinst.com>
Date: Mon, 7 Nov 2022 17:37:19 +0100
Subject: [PATCH 1/2] Fix support of sequence protocol for returned lists

Add the `sequence` option to PyO3's `pyclass`, so that the `sq_length`
slot is implemented [1]. Implementing this method is required for
sequence types, or Python C API functions like `PySequence_Size` will
fail with an error.

The `reversed` built-in method relies on `PySequence_*` methods. A test
reversing `NodeIndices` is added to guard against future violations of
the sequence protocol.

Fixes #696.

[1]: https://github.com/PyO3/pyo3/pull/2567
---
 src/iterators.rs                                  | 2 +-
 tests/rustworkx_tests/test_custom_return_types.py | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/iterators.rs b/src/iterators.rs
index 3a403d492..b6e496cc5 100644
--- a/src/iterators.rs
+++ b/src/iterators.rs
@@ -475,7 +475,7 @@ impl PyConvertToPyArray for Vec<(usize, usize, PyObject)> {
 macro_rules! custom_vec_iter_impl {
     ($name:ident, $data:ident, $T:ty, $doc:literal) => {
         #[doc = $doc]
-        #[pyclass(module = "rustworkx")]
+        #[pyclass(module = "rustworkx", sequence)]
         #[derive(Clone)]
         pub struct $name {
             pub $data: Vec<$T>,
diff --git a/tests/rustworkx_tests/test_custom_return_types.py b/tests/rustworkx_tests/test_custom_return_types.py
index 8abf87ae2..2362f125b 100644
--- a/tests/rustworkx_tests/test_custom_return_types.py
+++ b/tests/rustworkx_tests/test_custom_return_types.py
@@ -174,6 +174,12 @@ def test_slices_negatives(self):
         self.assertEqual([2, 3], slice_return)
         self.assertEqual([], indices[-1:-2])
 
+    def test_reversed(self):
+        indices = self.dag.node_indices()
+        reversed_slice = indices[::-1]
+        reversed_elems = list(reversed(indices))
+        self.assertEqual(reversed_slice, reversed_elems)
+
     def test_numpy_conversion(self):
         res = self.dag.node_indexes()
         np.testing.assert_array_equal(np.asarray(res, dtype=np.uintp), np.array([0, 1]))

From b4349a3e9639cb54e1269b379318462642056043 Mon Sep 17 00:00:00 2001
From: Matthew Treinish <mtreinish@kortar.org>
Date: Tue, 8 Nov 2022 15:36:54 -0500
Subject: [PATCH 2/2] Add release note

---
 .../notes/fix-sequence-protocol-e95246e864cc850a.yaml  | 10 ++++++++++
 1 file changed, 10 insertions(+)
 create mode 100644 releasenotes/notes/fix-sequence-protocol-e95246e864cc850a.yaml

diff --git a/releasenotes/notes/fix-sequence-protocol-e95246e864cc850a.yaml b/releasenotes/notes/fix-sequence-protocol-e95246e864cc850a.yaml
new file mode 100644
index 000000000..4bfb6fe37
--- /dev/null
+++ b/releasenotes/notes/fix-sequence-protocol-e95246e864cc850a.yaml
@@ -0,0 +1,10 @@
+---
+fixes:
+  - |
+    Fixed an issue with the custom sequence return types,
+    :class:`~.BFSSuccessors`, :class:`~.NodeIndices`, :class:`~.EdgeList`,
+    :class:`~.WeightedEdgeList`, :class:`~.EdgeIndices`, and :class:`~.Chains`
+    where they previosuly were missing certain attributes that prevented them
+    being used as a sequence for certain built-in functions such as
+    ``reversed()``.
+    Fixed `#696 <https://github.com/Qiskit/rustworkx/issues/696>`__.